Conventional helical gears have, for example, a spindle and a spindle nut, the internal thread of which is engaged with a thread of the spindle. A rotary drive of the spindle nut or of the spindle moves the other part, i.e., the spindle or the spindle nut, in an axial direction. Apart from those having sliding threads, there are also thread drives including rolling elements, for example, as ball thread drives or roller thread drives. Generally, the spindle nut or the spindle may also be regarded as a component of a helical gear which is rotatable, axially fixed and having a thread, and the other part, i.e., the spindle or the spindle nut may be regarded as a component of a helical gear which is axially movable, non-rotatable and having a counter-thread. The thread and the counter-thread are directly and indirectly engaged, for example, via rolling elements, so that a rotary drive of the rotatable component of the helical gear displaces the axially movable component in an axial direction.
Likewise, planetary gears are known which include a sun wheel and planetary wheels, which mesh with the sun wheel and rotate around the sun wheel in the presence of a rotary drive, and which include an annulus wheel enclosing the sun wheel concentrically, with which the planetary wheels also mesh and in which they rotate in the presence of a rotary drive and. The planetary wheels are situated eccentrically and rotatably on a planetary carrier, which is situated coaxially to the sun wheel and to the annulus wheel.